胃癌细胞株SGC-7901生长抑素2型受体表达和外源性生长抑素类似物的影响

目的: 观察胃癌细胞株SGC-7901生长抑素2型受体(SSTR-2)表达及外源性生长抑素类似物(SSA)对胃癌细胞生长和SSTR-2 mRNA表达的影响。 方法: 体外培养人胃癌细胞株SCG-7901,制作细胞爬片,免疫细胞化学染色法检测其SSTR-2表达。在RPMI-1640培养液中加入SSA,使SSA终浓度分别为0、10^-4、10^-5、10^-6mmol/L,培养0、24、36、48、72h,MTT法测定肿瘤细胞生长情况、RT-PCR法和计算机图像分析法,检测SSTR-2 mRNA表达情况。 结果: 免疫细胞化学染色法检测显示100%的SGC-7901细胞呈SSTR-2染色阳性,主要位于细胞膜上,部分胞浆也有染色。培养24h～72h1,×10^-4～1×10^-6mmol/L浓度的SSA可以使肿瘤细胞生长平均被抑制17.86%～40.48%。当SSA浓度为1×10^-4和1×10^-5mmol/L时,72h时其抑制率分别为17.86%和21.43%,与其他时间点的差异有显著性意义(P<0.001和P<0.01)。当SSA浓度为1×10^-6mmol/L时,对肿瘤细胞的抑制作用呈时间依赖性,72h时抑制率达到40.48%,显著高于1×10^-4和1×10^-5mmol/L组(P<0.001)。SGC7901细胞SSTR-2mRNA表达阳性;当SSA浓度为1×10^-4、1×10^-5mmol/L时,SSTR-2mRNA表达下调1.35%～31.65%(P<0.05),其中36h、48h、72h时低于0和24h时(P<0.01)。SSA浓度为1×10^-6mmol/L时,各时间点的OD值差异没有统计学意义(P>0.05)。 结论: SGC-7901胃癌细胞株高表达SSTR-2mRNA和蛋白。适当浓度的SSA对SGC-7901细胞的抑制作用才呈现时间依赖性,并对SSTR-2mRNA表达没有影响。

The Inhibitory Effects of Somatostatin Analogue on the Expression of Somatostatin Receptor 2 in Gastric Cancer SGC-7901 Cells

Objective: To investigate the expression of somatostatin receptor 2 (SSTR-2) in gastric cancer SGC-7901 cells and to observe the effects of somatostatin analogues (SSA) on cell proliferation and the expression of this receptor. Methods: SGC-7901 cells were cultured in vitro. The expression of SSTR-2 was assessed by SP immunocytochemistry. After these cells were treated with SSA at 0, 1×10^-4, 1×10^-5, and 1×10^-6mmol/l for 24h, 36h, 48h, and 72h, the cell proliferation was detected by MTT assay and the expression of SSTR-2 mRNA was assessed by RT-PCR. Results: The positive rate of SSTR-2 in SGC-7901 cells was 100%. SSTR-2 was located mainly on the membrane and partially in the cytoplasm. Those cells treated with SSA (1×10^-4～1×10^-6 mmol/l) for 24h~72h presented with a decrease (17.86%～40.48%) in cell growth. SSA at 1×10^-6mmol/l had a time-dependent inhibitory effect on the cancer cell growth, and the maximal inhibitory rate was 40.48% at 72h. When SSA was administered at 1×10^-4 and 1×10 ^-5mmol/l, the expression of SSTR-2 mRNA was reduced by 1.35%～31.65%. SSA at 1×10^-6 mmol/l did not affect the expression of SSTR-2 mRNA. Conclusion: The SSTR-2 was highly expressed on SGC-7901 cells. Without any effect on the expression of SSTR-2 mRNA, SSA at appropriate concentrations can time-dependently inhibit the cell growth.